The present invention relates to a soldering jig.
Soldering jigs are used in many areas of technology when it is desired to solder two or more parts together with very accurate placement of one part relative to another. Such soldering jigs are often used when the soldering of the parts is to be accomplished in a furnace, for example in those types of furnaces which surround a conveyor system on which the parts are continually moving. The soldering jigs hold the parts to be joined in desired relative positions until solidified solder can hold the parts rigidly together.
When high demands on the accuracy of the soldering is necessary, such as is the case in certain electrical applications, for instance semiconductor technology, the soldering jigs must themselves satisfy high requirements for dimensional accuracy and stability. Such soldering jigs can only be made of materials which suffer no ill effects at the temperature of the molten solder and which do not react with the melt. Neither should there be reactions of the solder with the material of the soldering jig, nor should there be a destruction of the soldering jig by reactions between solder and soldering jig at the requisite soldering temperatures and the usually strongly reducing conditions in the soldering furnace. Additionally, a semiconductor soldering jig must not have a negative influence on the electrical properties of the semiconductor elements. For instance, it must not cause instability in blocking ability, such as movement and very high reverse currents in the voltage-current curve of a blocking characteristic.
It is known to make soldering jigs of carbon, metals and ceramics. The use of these materials, however, gives rise to certain disadvantages.
Soldering jigs of carbon do not maintain their dimensions over extended periods of use, because the carbon tends to chip. Especially in complex soldering jigs, this chipping can lead to loss of accurate holding of the parts to be soldered together and thus to unusable end products. This problem is especially critical in semiconductor technology.
Soldering jigs of metal are expensive to manufacture and this problem is especially critical where many jigs are necessary. Each jig must be separately worked by boring, turning, milling or grinding processes. Metal soldering jigs can also damage the parts to be soldered together, especially when the parts are of delicate construction. Thus, the applicability of soldering jigs of metal is considerably limited.
Inexpensive soldering jigs of ceramic materials, when unglazed, have the disadvantage of comparatively rough surface. Moreover, such jigs can be difficult to produce, because the shrinkage during firing can not be accurately predicted. Application of glaze further worsens the problem of obtaining accurate jig dimensions. It is also extremely difficult to adjust the dimensions of a fired ceramic jig.